Electrode assembly



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0:. #Vn/50M United States Patent ELECTRODE ASSEMBLY Eugene 0. Hanson,Marion, Ind., assignor to Radio Corporation of America, a corporation ofDelaware Application August 25, 1955, Serial No. 530,531 6 Claims. (Cl.313-82) This invention relates to an improved electrode assembly and,particularly, to an improved means for supporting and mounting anelectrode assembly within a container.

The principles of the invention may be embodied in electrode assembliesof the type employed in cathode ray tubes, photo-tubes, and the like.Normally, a cath ode ray tube for television or other purposes includesan envelope having a large bulb portion and a tubular neck portion.Mounted within the tubular neck portion are a plurality of electrodesjoined together to provide an electrode assembly or an electron gun forforming and focusing an electron beam along a path extending into thebulb portion. For optimum control of the electron beam in such a tube,the electronl gun should be accurately and securely supported andcentered within the neck portion of the tube.

There are many known methods and means for mounting an electron gun inthe neck of a cathode ray tube. One type of mounting means includeselongated, ilat, double-ended metal spring support elements or spacershaving one end secured to one of the electrodes of the electron gun andhaving the other end pressing against the inner wall of the neck portionof the tube. Generally, it has been necessary to weld the support orspacer elements to the selected electrode of the gun in order to achievea strong assembly. However, a welding operation s comparativelyexpensive .and timeconsuming and is generally undesirable in massproduction operations. If welding is not employed, it has been founddifficult to attach the spacers to the gun electrodes to providepositive support of the gun within the tube neck.

In addition, such spacers of the prior art undergo considerable bendingwhen an electrode assembly is put together and then inserted into andadjusted Within a container. Such manipulation cold-works the metal ofthe spacers and they become fragile and are easily broken.

Accordingly, an object of this invention is to provide an improvedmounting and support means for an electrode assembly.

Another object of this invention is to provide improved means forcentering and supporting an electrode assembly in a container, saidmeans being easily and securely fastened to the assembly.

Another object of the invention is to provide irnprovcd centering andsupport means for an electrode assembly, said means being securely butremovably fastened to said assembly.

A further object of the invention is to provide an improved means formounting .and supporting an electrode assembly, said means being adaptedto absorb without adverse eiect, the stresses ordinarily accompanyingthe positioning of said electrode assembly Within a container.

Still another object of the invention is to provide an improved electrongun and means for mounting the same in an electron tube envelope.

In general, the principles and objects of the'invention are accomplishedby the provision of a plurality of electrodes secured together in anunitary assembly. One of the electrodes of the assembly has an aperturedend plate which includes a peripheral rim. Support elements forsupporting and centering the electrode assembly within a container suchas-the envelope of a cathode ray tube are secured to the peripheral rimof the last-mentioned electrode. The support elements include endportion which comprises a hook adapted to engage a hole just inside theperipheral rim of the end plate. The support elements also include agenerally C-shaped spring clamp portion which is adapted to snap ontoand securely grip the peripheral rim of the end plate. The C-shapedspring clamp portion alsoabsorbs strains induced during manipulation ofthe assembly. In securing a support element to the apertured plate, theAhook is first secured to the plate and then by pivoting the Supportelement about the area of connection between the hook and the plate, thespring clamp portion is brought into contact with the peripheral rim andis snapped onto the rim. The support elements `are also provided withone or more arms which are formed and adapted to press against the wallof the container in which the electrode assembly is mounted.

The invention is described in ence to the drawing wherein:

Fig. 1 is an elevational view, partly in section, of a cathode ray tubeincluding an electrode assembly embodying the principles of theinvention;

Fig. 2 is a sectional View along the line 2 2 in Fig. l;

Fig. 3 is a sectional elevational view of a portion of the electrodeassembly of Fig. 1 and a modification of the invention employedtherewith; and

Fig. 4 is a side elevational view of the embodiment of the inventionshown in Fig. 3.

An electrode assembly embodying the principles of the invention may beemployed in many different types of electrical apparatus. In thefollowing description, the invention is embodied in a cathode ray tube.

As shown in Fig. l, a cathode ray tube includes an envelope 12comprising a generally tubular neck portion 14 having a closed end orstem 15 secured to a plastic base member 16. The envelope also includesan enlarged bulb portion 17 having a glass face plate 18 on the innersurface of which is formed a phosphor screen.

Mounted within the tubular neck portion 14 is an electrode assembly 20which comprises an electron gun and which is supported in part by Wire'leads 21 welded thereto and secured in some suitable fashion to the stem15. The electron gun 20 includes a cathode electrode disposed within anenclosing tubular control grid elec.- trode 24. Accelerating electrodes26 and 28 are provided for promoting the formation of an electron beamand for directing the beam toward the on the face plate 18. In onesuitable construction, the electrodes 24, 26, and 28 are securedtogether by means of studs 30 extending from each electrode and embeddedin an insulating rod 32 of glass or the like.

In one type of electron gun, the electrode 28 is employed as an electronaccelerating electrode and comprises (Fig. 2) a tubular metallic memberclosed at one end by a circular plate 36 having a central aperture 38and a generally smoothly rounded rim portion 40. The plate 36 is alsoprovided with a plurality of generally rectangular openings 39 spacedapart equal distances on a common circumferential line. The electron gun20 is secured and centered Within the neck 14 of the envelope 12 bymeans of a plurality of support elements 46 which embody the principlesof the invention and which are secured to the electrode 28. The supportelements 46 contact a conductive coating 48 provided on the innersurfaces of the tubular neck 14 and the greater detail by referphosphorscreen y bulb portion 17. Auxiliary apparatus such as a deflection yoke49 and a focus coil 50 are provided for controlling the movement of theelectron beam generated by the electron gun 20.

As shown in Fig. 2, the support elements 46 which support and center theelectron gun assembly within the neck portion 14 of the cathode ray tubeErtl, are spaced apart equal distances about the axis of the gun andcomprises thin, elongated resilient metal strips of nickel or the like.Each support element includes means for securing the element to the endplate and providing a pivot point around which the element is rotatedwhen it is clamped to the end plate. The aforementioned means maycomprise a hook 54 adapted to be secured to the end plate 36 by beinginserted into one of the openings 39. The hook 54 includes two portions42 and 44 offset from each other and extending in opposite directions.

Adjacent'to the hook 54, the support element includes a generallyC-s'haped spring clamp portion 56 adapted to snap onto the rim 4t) ofthe plate 36 and to be retained in frictional locking engagementtherewith. The support element also includes an arm S8 which extendsfrom the C-shaped spring clamp portion to the other end of the elementwhich makes intimate contact with the conductive coating 48 on the innerwall of the neck of the tube. The last-mentioned end of the supportelement is formed with a generally spherical or otherwise suitablyshaped embossment 60, which insures intimate contact with the coating 48without damaging the coating. Each support element 46 may mostconvenienly be attached to the rim 40 by first inserting the hook 54into the opening 39 and then by bending the support element about thehook 54 as a pivot point. The C-shaped clamp portion 56 is snapped ontothe rim.

There is shown in Fig. 3, a modied support 62 secured to an end plate36' of an accelerating electrode 28. The support element 62 isparticularly suited for supporting and centering massive electron guns.The support element includes a hook 54', a C-shaped spring clamp portion56', an arm 5S and an end embossment 60', all of which are the same asthe corresponding parts of the support elements 46. The support element62 also includes an arm 64 which is secured at one end to the C- shapedspring clamp portion 56 and extends therefrom in a direction opposite tothat in which the arm 58 extends. The arm 64 also has an end embossment66 for providing intimate contact with a conductive coating 48' on theinner wall of a neck 14. Thus, the support member presses against thewall of the neck at two places and provides good support for theelectron gun.

As shown in Fig. 4, the support element 62 may be conveniently made froma single strip of sheet metal having the arms 58' and 64 formed bysuitable bending of the strip and having the hook 54 punched out of thestrip just above the C-shaped spring clamp portion 56'.

Support elements of the type described herein provide secure engagementwith an electrode assembly without being bonded thereto by welding or bysome similar operation. In addition such support elements allow mountingand manipulation of an electrode assembly within a container withoutbecoming detached and, within the container, they provide good supportand accurate centering of the assembly. In addition, the inventionprovides electrode support elements which may be manipulated withoutbecoming fragile from being coldworked.

What is claimed is:

l. An electrode assembly including a plurality of electodes axiallyaligned and secured together as a unitary assembly, one of saidelectrodes having a rim, and means for securing and centering saidassembly within a container, said means comprisnig a plurality ofresilient elongated metal strips having generally C- shaped spring clampportions at one end in transverse frictional gripping engagement withand substantially surrounding said rim of said one of said electrodes.

2. An electrode assembly adapted to be mounted in a container andincluding a plurality of tubular electrodes axially aligned and securedtogether as a unitary assembly7 one of said electrodes having a rim, andmeans for securing and centering said assembly within a container, saidmeans comprising a plurality of resilient metal strips having springclamp portions in transverse frictional gripping engagement with andsubstantially circumjacent said rim of said one of said electrodes andspaced apart about the periphery thereof, said spring clamp having aninternally offset end section engaging a surface of said electrode.

3. A cathode ray tube comprising an envelope having a neck portion, anelectron gun disposed within said neck portion and including a pluralityof electrodes axially aligned and secured together as a unitaryassembly, one of said electrodes having a surface and a rim, and meansfor securing and centering said electron gun within said neck portion,said means comprising a plurality of resilient metal strips havinggenerally C-shaped spring clamp portions at one end and a generallyspherical embossment at the other end, said strips being spaced apartabout the periphery of said one electrode with said C-shaped springclamp portions surrounding and independently gripping said rim, saidC-shaped spring clamp portion having a hook extending through and alongthe surface of said one electrode, said spherical embossments in contactwith the wall of said neck portion.

4. A cathode ray tube comprising an envelope having a neck portion, ankelectron gun disposed within said neck portion and including a pluralityof tubular electrodes axially aligned and secured together as a unitaryassembly, one of said electrodes having a rim, and means for securingand centering said electron gun Within said neck portion, said meanscomprising a plurality of resilient metal strips, each of said stripsincluding a C- shaped spring clamp portion and a pair of arms extendingtherefrom in substantially opposite directions, each of said arms beingin contact with the inner wall of said neck portion and said C-shapedspring clamp portion being secured to said rim.

5. An electron gun including a plurality of electrodes axially alignedand secured together as a unitary assembly, one of said electrodeshaving an end plate including a rim, and means for securing andcentering said electron gun within the envelope of a cathode ray tube,said means comprising a plurality of resilient metal strips havingspring C-clamp portions in frictional gripping engagement withtransversely surrounding said rim of said one of said electrodes.

6. A support member for supporting an electron gun comprising a strip ofmetal including a hook-like process at one end thereof adapted to beengaged within an opening in one of the electrodes of said electron gun,a generally C-shaped spring clamp portion adjacent to said process andadapted to be secured in frictional locking engagement with a portion ofsaid electron gun and a process at the other end for making contact witha wall portion of an electron tube, a pair of arms extending from saidC-shaped portion in substantially opposite directions, and a process atthe end of each of said arms for making contact with a wall of a cathoderay tube.

References Cited in the le of this patent UNITED STATES PATENTS2,225,099 Christaldi Dec` 17, 1940 2,269,115 Koch Jan. 6, 1942 2,432,037OLarte et al. Dec. 2, 1947 2,592,242 Campbell Apr. 8, 1952 2,638,559 vGiacchetti May 12, 1953 2,719,243 Hoagland Sept. 27, 1955

